not getting where going wrong

You should initialize an object in setCatCount Cat.object= new Cat(); and give object.catCount(private variable)=catCount(Local variable of setCatCount) call the setCatCount from main method with an int argument setCatCount();

//This works for me package com.codegym.task.task04.task0405; //The Cat class's setCatCount method must set the value of the catCount variable equal to the passed argument //Write the setCatCount method. The method must set the number of cats (catCount) public class Cat { private static int catCount = 0; public static void setCatCount(int catCount) { Cat.catCount = catCount; System.out.println(catCount); } public static void main(String[] args) { Cat.setCatCount(21); } }

You have the catCount set to '0' already as a field in the Cat class. Now in the method, have catCount = Cat.catCount; This way you are stting the catCount to the passed argument.